句子成分判定

I think that parents are the best teachers to the children is not always accurate because parents sometimes will do some negative effect to their children.
正确。
从that到children（句末）部分整个为think的宾语。
从parents到children（句中）部分是宾语从句中的主语从句。
从because到children（句末）是宾语从句中的原因状语从句。

正确
“parents are the best teachers to the children is not always accurate because parents sometimes will do some negative effect to their children”整个是“I think”的宾语

这句话总体是个宾语从句,其中含有主语从句.

I 是主语,think是谓语

that后边引导的句子 parents are the best teachers to the children is not always accurate 是宾语从句的内容.宾语从句本身又是一个主语从句.is 之前是主语,之后是表语.

because后边引导的是原因状语.